



Low Level Event Handling


import java.awt.*;
import java.applet.*;
import java.awt.event.*;

class CBG extends Checkbox{

  cbgb CB;

  CBG(String s, CheckboxGroup c, boolean b, cbgb cb) {
    super(s, c, b);
    CB=cb;
    enableEvents(AWTEvent.ITEM_EVENT_MASK);
  }

  public void processItemEvent(ItemEvent i){
    CB.s=CB.cg.getSelectedCheckbox().getLabel();
    CB.repaint();
  }
}

public class cbgb extends Applet{
  CheckboxGroup cg;
  CBG a, b, c, d, e, f;
  String s;

  public void init(){
    setBackground(Color.yellow);
    cg = new CheckboxGroup();
    a = new CBG("Checkers", cg,  false, this);
    b = new CBG("Polka Dots", cg, false, this);
    c = new CBG("Stripes", cg, false, this);
    d = new CBG("Solid", cg, true, this);
    e = new CBG("Diamonds", cg, false, this);
    f = new CBG("Donuts", cg, false, this);
    add(a); add(b); add(c); add(d); add(e); add(f);
    s="Solid";
  }

  public void paint(Graphics g){
    g.setColor(Color.black);
    if(s.equals("Solid")) {}
    else if(s.equals("Checkers")){
      for(int x=20; x<180; x+=40)
        for(int y=80; y<240; y+=40){
          g.fillRect(x,y,20,20);
          g.fillRect(x+20,y+20,20,20);
        }
    }
    else if(s.equals("Donuts")){
      for(int x=20; x<180; x+=40)
        for(int y=80; y<240; y+=40){
          g.setColor(Color.black);
          g.fillOval(x,y,30,30);
          g.setColor(Color.yellow);
          g.fillOval(x+10,y+10,10,10);
        }
    }
    else if(s.equals("Stripes")){
      for(int y=80; y<240; y+=10){
        g.fillRect(20,y,160,5);
      }
    }
    else if(s.equals("Diamonds")){
      for(int x=20; x<180; x+=40)
        for(int y=80; y<240; y+=40){
          int pxs[] = {x, x+10, x, x-10};
          int pys[] = {y, y+10, y+20, y+10};
          g.fillPolygon(pxs, pys, 4);
        }
    }
    else if(s.equals("Polka Dots")){
      for(int x=20; x<180; x+=40)
        for(int y=80; y<240; y+=40){
          g.setColor(Color.red);
          g.fillOval(x-5,y+10,12,12);
          g.setColor(Color.blue);
          g.fillOval(x+10, y, 18,18);
          g.setColor(Color.magenta);
          g.fillOval(x-5, y+20, 24,24);
          g.setColor(Color.green);
          g.fillOval(x-5, y-10, 20,20);
        }
    }
  }
}


//<applet code=cbgb.class height=300 width=300></applet>